How Much Weight Can Safely Be Lost with Smart Lipo?

Liposuction rarely results in any weight loss unfortunately. The fat that is contained in the body is actually very light (sort of like feathers), but takes up a bit of space. Usually, even a 2 to 3 liter liposuction won't result in more than a pound of weight loss.
It sounds like you need more than this and may even want to consider bariatric surgery. While this won't usually do anything for 'loose skin', it has a track record of weight loss. Good luck.

Expert liposuction surgeons tend to use liposuction to reduce body disproportion rather than as a weight loss tool. The goal of lipo is to improve body contour. Best. Dr. Karamanoukian

Liposuction is for spot reduction, not for weight loss. Although you won't see a big difference in how much you lose, you will see the areas that you got treated reduce in circumference. So, after you get your surgery, don't look at the scale. Instead, look in the mirror to see if you like what you see.

You should reach your ideal stable weight first before proceeding with any cosmetic surgical body contouring procedure. Being within a normal BMI range dramatically improves your surgical outcome and is safer for you as well. Smartlipo is not a form of weight loss. It is only for localized fat deposits that you weren't able to get rid of through exercise and diet alone.

Please remember as others have rightfully said, any form of lipo is about targeting disproportionate stubborn areas of fat and not for losing weight. This reproportioning and contouring is the surgeons responsibility. The weight loss is yours. But if you mean how much fat can be removed with liposuction surgery safely at one time it has been defined as 5 liters whether done under local tumescent or general anesthesia. This equates to about 12 pounds of pure fat. But remember also that a perfect result natural looking result is so should not be measured by how much fat was removed but by how great looking the result is.